The "Parry Series" chess problem genre was discovered by your host in April 2009, and the chess problem aim known as "CapZug" in July 2010. This page will serve as a repository for all Parry Series and CapZug developments.

Definition:

A parry series-mover differs from a standard series-moverprior to the last move as follows:

the series-side may give check during the series

when checked, the idle-side must immediately parry the threat

a parry-move may be helpful or defensive, depending on the problem-type

after a check-and-parry, the series-side continues the series

Follow the links below to see Parry Series examples, articles, and related webpages.

April 2009: Your host stumbled upon a new series concept which was first named "CheckReflex". Soon thereafter, it became apparent that we were dealing with an entirely new genre -- a hybrid of series and non-series. The name Parry Series seemed natural, and is unique in Problemdom.

July 2009: With the help of several composers, Parry Series was ready to be introduced within a few weeks! The article, Parry Series: A New Frontier, debuted in the July-September issue of StrateGems (SG47), with 12 originals. That same issue featured 7 more parry series-movers in the Series-Movers & Stalemates column.

For simplicity, parry series-movers are denoted as: pser-*. When Popeye was upgraded [see January 2010 entry below], the form phser-* was also implemented to accommodate less-common problem types with helpful parries.

September 2009: The Canadian series advocate Cornel Pacurar founded the Parry Series Workshop. The PSW is a private area of his general series forum, so registration is required to participate in the on-going discussions. Needless to say, the PSW has been instrumental in furthering Parry Series exploration!

November 2009: The Good Companions (the informal association of U.S. composers) announced two formal "quick-tourneys": section-A for Parry Series and section-B for Proofgames. The deadline for entries was Feb. 15th, 2010. Word of the GCQCTs spread via emails, and discussion on the popular MatPlus website.

January 2010: While the GCQCT was still under way, Thomas Maeder upgraded the Popeye solving program for all Parry Series types -- a major breakthrough. Since composers could now test (or partially test) any type of parry series-mover, the number (and quality) of entries for the GCQCT (section-A) increased steadily. We cannot thank Thomas enough for making these coding changes on such a tight schedule!

May 2010: Solvers should enjoy these two just-published originals! [The second item is a help-auto-stalemate. So... white plays the series and black parries to help. White's 14th series-stalemates himself!]

16-Jul-2010: One of the "theoretical" points made in Petko's article is that an all-checks Parry Series should be classified as 'Black Must Check' or 'White Must Check', also known as "UltraSchachZwang" (USZ). I beg to differ!

The condition 'must-check' is intended to facilitate soundness (ie. eliminate cooks and/or duals), not to merely describe the play that ensues. Thus, a USZ problem that is sound without the 'must-check' requirement is improperly classified. And that means you cannot simply re-label a Parry Series as USZ.

Also, a legitimate USZ cannot be stipulated as Parry Series. That is, if the 'must-check' proviso is truly necessary, then may-check (as in Parry Series) cannot be sound. Conclusion:An all-checks Parry Series cannot be classified as "USZ". And vice versa.

25-Jul-2010: This brief article shows that Parry Series is not as 'new' as we thought. Enjoy!

Legal Parry Series (denoted as legal-pser-*) was invented by Valery Liskovets of Belarus. LPS is like normal parry-series except that the idle-side moves when in-check and when they have no prior move! This clever twist adds a retro element to the Parry Series protocol.

CapZug (stipulated as "x=") (*) is a new aim invented by yours truly. CapZug is short for Capture-Zugzwang, and is achieved when the side on-move (1) is not in-check, and (2) would be compelled to make a capture. For more details and examples, see the Good Zug Tourney announcement. (*) CapZug notation changed from x= to xz! See the 10-Apr-2011 post below.

28-Oct-2010: The WCCC-53 Bulletin contains the Good Zug Tourney (GZT) 2010 results on page 48. Of course, there are lots of other goodies as well. :-) Some sample award-winners from the GZT are given below:

19-Dec-2010: A new article, Parry Series Chronicles, can be found in feenschach f181, available in both English and German text. Thanks to Arno Tüngler for his excellent translation! Some sample originals from the article are given below:

10-Apr-2011: The notation for CapZug must be changed to usher in the "Zug Family" of stipulations! See the preview article here for details. We recommend that editors and publishers use xz (rather than x=) to represent CapZug going-forward, for reasons stated in the article.

16-May-2011: I completed judging for the ChessProblems.ca 2010 Series Tourney. Click here to view or download the awards PDF. Both Parry Series and CapZug are represented.

04-Oct-2011: I published this formal response to Petko's SG51 article (see July 2010 post above) in the latest StrateGems, in light of some recent discussions re: Parry Series vs. other existing check-based conditions. I've paraphrased my thoughts on this subject (originally posted on MatPlus Forums) below:

Parry Series is a better presentation than non-series forms with XMOWIC (player-X moves only when in check) condition. Why? Because the latter discloses the fact that the last move (for one side) must be a check -- at least for help- and self-problems.

Parry Series is a better presentation than non-series forms with a must-check proviso. Why? Because the latter discloses the fact that all moves (for one side) must be checks.

It is not incumbent upon a composer to unnecessarily divulge information about a problem's intent (or content). Thus, Parry Series is the correct presentation in such cases.

November 2011: Arno's long-awaited "Zug Family" article was published in feenschach/f188!&nbsp&nbspClick here to view it.&nbsp&nbspNote: The wK should be on e4 in problem number Z12 (Kirtley).

January 2012: The release of Popeye v4.59 introduces a new sstip protocol which affects Zug-Family problem testing.&nbsp&nbspClick here to visit the Popeye download page.&nbsp&nbspClick here to download the Zugzwang Goal Sstips for Dummies cross-reference to help setup Popeye for "zug" problem tests. (updated 11-Jan-2012)